Paragrilus tenuis

(LeConte, 1863)

Paragrilus tenuis is a small metallic wood-boring beetle in the Buprestidae, one of four Paragrilus occurring in the United States. are approximately 5 mm in length and are associated exclusively with plants in the Hibiscus, particularly H. moscheutos (including ssp. lasiocarpos) and H. laevis. The species has been reared from living stems of its plants, distinguishing it from most Agrilus species that utilize dead wood. It occurs in natural from New York south to Florida and west to Missouri and Mississippi.

Pronunciation

How to pronounce Paragrilus tenuis: /pæˈræɡrɪləs ˈtɛnjuɪs/

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Identification

Paragrilus tenuis can be distinguished from the much larger and more common Agrilus by its , which are received in grooves () along the sides of the pronotum when the tucks its defensively. are small (~5 mm), with the typical elongate, somewhat flattened body form of agriline buprestids. The genus Paragrilus is distinguished from Agrilus primarily by antennal structure and larval —Paragrilus larvae develop in living herbaceous stems rather than dead woody branches. Among the four U.S. Paragrilus , P. tenuis is the only one occurring in the eastern United States.

Habitat

Associated with natural stands of Hibiscus in wetland and lowland , including wet bottomland forests and marsh edges. are found on terminal leaves of plants. Has been observed in sand prairie remnants and conservation areas with native Hibiscus . Not reported from cultivated Hibiscus varieties.

Distribution

North America: New York south to Florida and west to Missouri and Mississippi. Documented in the southeastern lowlands of Missouri (Stoddard County), Virginia (George Washington Memorial Parkway), and Oklahoma.

Seasonality

active during spring and early summer, with records from May through July. Peak activity likely coincides with Hibiscus growth and flowering periods.

Host Associations

  • Hibiscus moscheutos - larval including lasiocarpos
  • Hibiscus laevis - collected on this but not yet reared
  • Hibiscus lasiocarpus - associationobserved at Otter Slough Conservation Area, Missouri

Life Cycle

Larvae develop as stem borers in living stems of Hibiscus plants. This distinguishes the from most Agrilus , which utilize dead wood. emerge and are found resting on terminal leaves of plants.

Behavior

are extremely wary and quick to take when disturbed, making them challenging to observe and photograph. They typically rest on the upper leaf surfaces of plants, where they perch, mate, and feed.

Ecological Role

Larval stem-borer in living Hibiscus stems; may influence plant growth and stem architecture. Part of the specialized herbivore associated with native Hibiscus in wetland .

Human Relevance

Subject of entomological study due to its specialized association and as one of the few reared in the Paragrilus. First recorded from Virginia in 2012. Not considered an agricultural pest; restricted to native Hibiscus in natural .

Similar Taxa

  • Agrilus concinnusAlso associated with Hibiscus, but larger, more spectacularly colored with metallic green and coppery reflections, and lacks antennal grooves on pronotum. active later in season (late July–August) compared to P. tenuis.
  • Paragrilus burkeiAnother U.S. Paragrilus , but occurs in western North America (Arizona, New Mexico, Texas) and is associated with Sida species rather than Hibiscus.
  • Agrilus spp.Numerous in the same (Agrilinae) but distinguished by lack of antennal grooves on pronotum and typically associated with dead woody rather than living herbaceous stems.

Sources and further reading